Add flask_table for admin view

app/templates/main/admin.html.j2

@@ -1,11 +1,11 @@
 {% extends "base.html.j2" %}
 
 {% block page_content %}
-<h1>Administration tools</h1>
 <div class="col s12">
   <div class="card large">
     <div class="card-content">
       <span class="card-title">User list</span>
+      {{ table }}
     </div>
   </div>
 </div>